Phototherapy is utilized for various objects including treatment for a disease such as neonatal jaundice, psoriasis, or acne, alleviation of pain, and cosmetics. Green light and blue-white light are used for treatment for neonatal jaundice, ultraviolet light is used for treatment for psoriasis, and blue light, red light, and yellow light are used for treatment for acne. In this manner, various light sources are used in accordance with uses.
In NPL 1, a therapeutic method for methicillin-resistant staphylococcus aureus (hereinafter, referred to as “MRSA”) infected skin ulcer using near ultraviolet light is described. The therapeutic method is a method in which a part infected with staphylococcus aureus having antibiotic resistance is irradiated with near ultraviolet light (wavelength of about 410 nm) to thereby annihilate the bacteria, and is based on a process in which 5-aminolevulinic acid (hereinafter, referred to as “ALA”) subjected to systemic administration is, in the bacteria, metabolized to protoporphyrin IX (hereinafter, referred to as “PpIX”) and accumulated, and the bacteria is destroyed from an inside of the bacteria by active oxygen generated when the PpIX is decomposed by near ultraviolet light.
It is considered that the therapeutic method has a wide application range and highly promising as a technique by which a side effect is not caused to a cell itself in an affected part at all and which enables killing of a bacteria having antibiotic resistance without causing contamination by an antibiotic substance.
In order to spread such a technique, a light irradiation device that is able to uniformly radiate light to affected parts having various three-dimensional shapes and sizes is required.
Conventionally, a device using a light source such as an excimer lamp or an arc lamp, a device using a laser as a light source, a device of a system in which therapeutic light is radiated planarly by using an optical fiber, and the like have been known as the light irradiation device, for example.